The present invention relates to automotive transmission systems and, more particularly, to a hybrid torque converter for a GENERAL MOTORS (hereinafter “GM”) 4L80E transmission, which includes redesigned torque converter components for converting a stock GM 4T40E torque converter core for installation in a high performance GM 4L80E transmission.
For purposes of this application the term “hybrid” will be understood to define a torque converter having components with features and characteristics derived from two or more stock torque converters and, more particularly, a hybrid torque converter having component parts derived from both the GM 4T40E and the GM 4L80E torque converters. The term “stock” will be understood to define a torque converter assembly or a component thereof which is original equipment manufacture (hereinafter “OEM”) as distributed from GENERAL MOTORS Corporation.
Automatic overdrive transmissions have become the preferred setup of many street rod and racing enthusiasts. This technology allows the use of low gear ratios for performance while not interfering with highway cruising and fuel mileage due to the substantial revolutions per minute (hereinafter “RPM”) reduction that their fourth gear overdrive provides.
The GM 4L80E automatic transmission is stock equipment for GM truck and SUV applications (e.g. Truck C/K series, Yukon, Suburban, Tahoe). With GM's latest refinements and electronic controls, the 4L80E transmission is stronger and much smarter than its predecessors. When modified for all-out performance, the GM 4L80E stands alone as the ultimate racing transmission setup and is the first choice of many high performance enthusiasts.
In contrast the GM 4T40E transaxle, which is stock equipment on mid-size passenger vehicles (e.g. Malibu, Cavalier), features many available stator and impeller combinations capable of delivering a wider range of torque multiplication and stall speeds (i.e. K-factors), which are matched to the torque curve of a particular engine. Advantageously, the GM 4T40E transaxle also features a smaller diameter (i.e. 245 millimeter) torque converter core having less rotating mass than its GM 4L80E counterpart.
Thus, the present invention has been developed to transform the more versatile, lightweight torque converter core of the GM 4T40E transaxle into a hybrid GM 4L80E torque converter for installation in a GM 4L80E transmission to improve its performance in selected applications.